Google's PUE

Marshall Eubanks tme at
Wed Oct 1 22:10:37 UTC 2008

On Oct 1, 2008, at 5:44 PM, Deepak Jain wrote:

>> I am going to attempt to determine our PUE, using the methodology  
>> described in the Google paper.  One must figure that "in the spirit  
>> it was intended" has to factor in the natural gas consumption,  
>> otherwise my PUE would be about 0.1.  :)
> If you generate energy for your microturbine from a land fill (free  
> methane gas) your PUE would be nearly zero. Obviously PUE can be  
> skewed and shouldn't be considered as a single metric for anything  
> other than a press release.
> I would also suggest that Alex shouldn't hold is breath on more  
> details. The details provided are interesting, but without context.

Indeed. If they would refuse a visit to Cory Doctorow writing for  
Nature, I don't think we should hold our breath at
all :

" It doesn't disclose the dimensions or capacity of those data  
centres. Nature wanted me to visit one for this piece, but a highly  
placed Googler told me that no one from the press had ever been  
admitted to a Google data centre; it would require a decision taken at  
the board level. Which is too bad."


> (Its like:
> "Hi, we filter our river water to evaporate it." But are they  
> calculating the cost of all that contaminated material and its  
> disposal? The blowdown on their cooling towers would have to be many  
> times more hazardous than normal, and may require additional  
> treatment to make it safe to release).
> Is any math being done to decide whether free river/water-side  
> economization is more important (financially/environmentally) than  
> cheap energy inputs?
> If rather than density, we REDUCE density and build very large foot  
> print data centers that can use ambient air (I've heard rumors that  
> MSFT is using 85 degree air [cool side] in New Mexico) we could get  
> to PUE numbers that were nearly ideal (hot air rises, natural  
> convection, no fans, just PDU overhead, etc).
> Except where it impacts the bottom line, this all seems more like a  
> fashion show than an actual business plan.
> Deepak Jain

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